I noticed the same effect some updates before, as I played against an AI-Teleport-Turtle. As AI number 1.So I though, the gatlings use the AI-profile from the turtle AI.

Now has a technology robber as AI number 1. And the same effect.In the beginnig they swarmed out (when hostile ships comes to the neighbour systems), but now they are very lazy.Cause no more hostile ships near them.